As shown in FIGS. 1-A, 1-B, and 1-C, the conventional knitting machine comprises a machine base A on which a needle platform A1 is mounted. Located behind the needle platform A1 is an oil tank A2 in which a transmission shaft B is located. The transmission shaft B is provided at one end thereof with a transmission wheel B1 for transmitting power of the motor in conjunction with a belt B2. The transmission shaft B is provided at both ends thereof with an actuation seat C of an eccentric construction and having a connection rod C1 which is connected with the needle platform A1 in conjunction with the support of a bearing seat C2. The transmission shaft B must be further provided with a plurality of bearing seats C2 and weighted blocks C3, so as to enable the transmission shaft B and the actuation seat C to engage in a fast back-and-forth motion to bring about the knitting operation. The transmission shaft B is always kept in the oil tank A2 which is sealed off to prevent the loss of oil. After a prolonged operation, the actuation seats C must be detached from the transmission shaft B for maintenance or repair work. It is rather time-consuming to dismount and mount the actuation seats C. In addition, the actuation seats C are connected with the needle platform A1 by the connection rod C1, the mechanical friction between the actuation seat C and the connection rod C1 is unavoidable. In other words, the actuation seats C are prone to wear. As a result, the linear motions of the actuation seats an the needle platform A1 are distorted.
Now referring to FIGS. 1-D and 1-E, the conventional transmission mechanism of a weft seat of a knitting machine comprises a transmission rod D, which is fitted into an eccentric shaft cylinder D2 located at the lower portion of a link seat D1 which is fastened at the upper portion thereof with a fastening member D3 which is in turn fastened with a link rod D4 by a bolt D41. The link rod D4 is connected with a weft seat D5 which is provided with a plurality of cross rods connecting a yarn guiding plate. The power of motor is transmitted to the link seat D1 via the transmission rod D. The link seat D1 is driven to engage in a fast up-and-down reciprocating motion, thanks to the operation of the eccentric shaft cylinder D2. The link rod D4 and the weft seat D5 are thus actuated by the fastening member D3. It is therefore readily apparent that the conventional transmission mechanism of the weft seat D5 of the knitting machine is composed of many component parts and is thus inefficient. In addition, the component parts must be often checked to make sure that they are in a proper working condition. Moreover, the transmission mechanism of the weft seat D5 is too complicated in construction and is therefore not cost-effective.